Administering fluids containing medicine or nutrition to a patient is well known in the art. Although fluids can sometimes be delivered to the patient by gravity flow, often a flow control apparatus, such as a peristaltic pump or the like, drives a pump set for delivering fluid to the patient at a controlled rate of delivery. A peristaltic pump suitable for use in administering fluids to a patient typically comprises a housing that includes at least one motor operatively engaged to a pump rotor through a gearbox. The motor is operatively connected to a rotatable shaft that drives the pump rotor, which in turn progressively compresses the tubing of the pump set. The peristaltic action effected by rotation of the pump rotor by the motor drives fluid through the tubing. A controller operates the motor, or motors, to drive the pump rotor and, thus, controls fluid flow. Other types of peristaltic pumps not employing pump rotors are also known.
In order for the pump to deliver a precise amount of fluid corresponding with flow parameters programmed into the pump controller, the pump set must be compatible with the pump and correctly loaded in the pump. For example, if the pump set is misaligned in the pump or is not compatible with the pump, the pump may deliver an inaccurate amount of fluid to a patient or generate a low flow alarm requiring the condition to be examined and the set reloaded or changed. Existing pumps have systems to detect whether the pump set is properly loaded. An example of such a pump having a detection system is shown in co-assigned U.S. Pat. No. 4,913,703, entitled SAFETY INTERLOCK SYSTEM FOR MEDICAL FLUID PUMPS, the entire disclosure of which is incorporated herein by reference. In this system, circuitry in the pump detects a magnet on the pump set to determine if it is compatible. Unfortunately, the use of a magnet adds to the cost and complexity of the pump set. Detecting a compatible pump set by use of electromagnetic radiation emitters and detectors is another solution, but ambient electromagnetic radiation from the sun and artificial light sources can interfere with accurately detecting emitted electromagnetic radiation signals.